forked from extern/nushell
522a828687
* Refactor InputStream and affected commands. First, making `values` private and leaning on the `Stream` implementation makes consumes of `InputStream` less likely to have to change in the future, if we change what an `InputStream` is internally. Second, we're dropping `Option<InputStream>` as the input to pipelines, internals, and externals. Instead, `InputStream.is_empty` can be used to check for "emptiness". Empty streams are typically only ever used as the first input to a pipeline. * Add run_external internal command. We want to push external commands closer to internal commands, eventually eliminating the concept of "external" completely. This means we can consolidate a couple of things: - Variable evaluation (for example, `$it`, `$nu`, alias vars) - Behaviour of whole stream vs per-item external execution It should also make it easier for us to start introducing argument signatures for external commands, * Update run_external.rs * Update run_external.rs * Update run_external.rs * Update run_external.rs Co-authored-by: Jonathan Turner <jonathandturner@users.noreply.github.com>
49 lines
1.1 KiB
Rust
49 lines
1.1 KiB
Rust
use crate::commands::WholeStreamCommand;
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use crate::prelude::*;
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use nu_errors::ShellError;
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use nu_protocol::{ReturnSuccess, ReturnValue, Signature, UntaggedValue};
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pub struct What;
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#[derive(Deserialize)]
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pub struct WhatArgs {}
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impl WholeStreamCommand for What {
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fn name(&self) -> &str {
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"describe"
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}
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fn signature(&self) -> Signature {
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Signature::build("describe")
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}
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fn usage(&self) -> &str {
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"Describes the objects in the stream."
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}
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fn run(
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&self,
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args: CommandArgs,
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registry: &CommandRegistry,
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) -> Result<OutputStream, ShellError> {
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args.process(registry, what)?.run()
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}
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}
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pub fn what(
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_: WhatArgs,
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RunnableContext { mut input, .. }: RunnableContext,
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) -> Result<OutputStream, ShellError> {
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let stream = async_stream! {
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while let Some(row) = input.next().await {
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let name = value::format_type(&row, 100);
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yield ReturnSuccess::value(UntaggedValue::string(name).into_value(Tag::unknown_anchor(row.tag.span)));
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}
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};
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let stream: BoxStream<'static, ReturnValue> = stream.boxed();
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Ok(OutputStream::from(stream))
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}
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